Silver halide color photographic materials typically have a multi-layer constitutional light-sensitive film, coated on a support, comprising three kinds of silver halide emulsion layers selectively sensitized so that the layers have light-sensitivity, usually, to blue-light, green-light, and red-light, respectively. For instance, a so-called color photographic paper (hereinafter referred to as "color paper") generally has a red-sensitive emulsion layer, a green-sensitive emulsion layer and a blue-sensitive emulsion layer coated on a support in in the order listed on the side to be exposed to light, and, in addition, color-stain preventive or ultraviolet absorptive intermediate layers, protective layers and the like are provided between the light-sensitive layers and so on.
For the formation of color photographic images, photographic couplers for three colors of yellow, cyan and magenta are incorporated in the light-sensitive layers, and the photographic materials are, after having been exposed to light, subjected to color development with a so-called color developer. The coupling reaction between the oxidation product of an aromatic primary amine and the coupler results in the formation of colored dyes; and the coupling speed in the reaction is preferably as high as possible, and the couplers are preferred to have a higher colorability so as to obtain a higher color density within the limited developing time. Moreover, the colored dyes are required to be sharp cyan, magenta, and yellow dyes, individually, with less side-absorption and to form color photographic images of good color-reproductivity.
In addition, the cyan-, magenta- and yellow-couplers are required to be fixed individually to the respective silver halide emulsion layers each having a selective sensitivity to blue, green, or red light to prevent color stain. Therefore, the couplers to be used in practice are to have a long-chain aliphatic group in the molecule as a diffusion-resistant group.
In the practical use of such couplers having an oleophilic diffusion-resistant group, in general, so-called oil-soluble couplers have heretofore been proposed, which are dissolved in a high-boiling point or low-boiling point organic solvents; and the resulting coupler solution is emulsified, dispersed and incorporated into an emulsion layer. The use of such couplers, however, is accompanied by difficult problems, such as that the color developing agent hardly penetrates into the coupler dispersion-containing oil drops, the said agent has a poor oleophilic property, and that the colored density is low. Under the circumstances, various kinds of developing agent penetrating accelerator have been investigated. In particular, the addition of benzyl alcohol to color developers for the acceleration of the color development has heretofore been widely utilized for the processing of color photographic materials, in particular, color papers, as the coloration-accelerating effect by the addition of benzyl alcohol is remarkable.
However, the use of benzyl alcohol requires diethylene glycol, triethylene glycol or alkanolamines as a solvent, since the benzyl alcohol has a poor water-solubility. These compounds including benzyl alcohol have high BOD (biochemical oxygen demand) and COD (chemical oxygen demand) values, which are environmental pollution load values, and therefore, the use of benzyl alcohol is preferably avoided in view of the purpose for the reduction of the environmental pollution load.
Moreover, even though the said solvents are used, the dissolution of benzyl alcohol in said solvents requires much time, and therefore, the use of benzyl alcohol is better avoided from the viewpoint of the purpose for the reduction of the load in the preparation of photographic processing solutions.
Further, if benzyl alcohol is brought into a bleaching bath or bleaching-fixation bath, which is a post-bath after the developing bath, this will result in the formation of a leuco dye of a cyan dye, causing the decrement of the colored density. In addition, the use of benzyl alcohol causes retardation of the speed for the washing-out of developer components, which often have a bad influence on the image preservation-stability of processed photographic materials. Accordingly, benzyl alcohol is preferably not used in view of the above-mentioned reasons.
Color development is, in general, completed within 3 to 4 minutes in conventional means, and recently, the reduction of the processing time is being required along with the reduction of the time limit for the delivery of commercial color prints and with the reduction of the working load in the development laboratory.
Despite such situation, the elimination of benzyl alcohol, which is a coloration-accelerator, and the reduction of the developing time, tend to cause a noticeable deterioration of the colored density.
In order to solve these problems, various other kinds of color development-accelerators (for example, compounds as described in U.S. Pat. Nos. 2,950,970, 2,515,147, 2,496,903, 2,304,925, 4,038,075 and 4,119,462, British Pat. Nos. 1,430,998 and 1,355,413, Japanese Patent Application (OPI) Nos. 15831/78, 62450/80, 62451/80, 62452/80, 62453/80, 50536/83 and 162256/85 (the term "OPI" as used herein means an "unexamined and published application"), Japanese Patent Publication Nos. 12422/76 and 49728/80) have heretofore been co-used together with various color developers, but fully satisfactory color density has not been obtained as yet.
The incorporation of color developing agents into photographic materials (for example, as described in U.S. Pat. Nos. 3,719,482, 3,342,559 and 3,342,597, Japanese Patent Application (OPI) Nos. 6235/81, 16133/81, 97531/82 and 83565/82) also is defective in that the speed of the color development is lowered and fog occurs, and this is not proper.
The use of silver chloride emulsions (for example, as described in Japanese Patent Application (OPI) Nos. 95345/83, 242342/84 and 19140/85) is not fully practical, since the occurrence of fog is noticeable.
Despite much work in this area, a method for the formation of fully sufficient color images in a short period of time by using color developers which do not substantially contain benzyl alcohol has not yet been found.